I have an array looking like this:

arr = ['a', 'b', 'c', 'd', 'e', 'f'];

How can I shift its values while maintaining the order. For instance, I'd like to start it with 'd':

new_arr = shiftArray(arr, 'd'); // => ['d', 'e', 'f', 'a', 'b', 'c']

I have an array looking like this:

arr = ['a', 'b', 'c', 'd', 'e', 'f'];

How can I shift its values while maintaining the order. For instance, I'd like to start it with 'd':

new_arr = shiftArray(arr, 'd'); // => ['d', 'e', 'f', 'a', 'b', 'c']

• javascript
• arrays
• sorting

Share Improve this question Follow asked Jul 9, 2015 at 12:37 idlebergidleberg 12.9k1010 gold badges4545 silver badges7171 bronze badges 4

• Are you sure your array is always unique? – axelduch Commented Jul 9, 2015 at 12:38
• Yes, it's populated by unique file-names – idleberg Commented Jul 9, 2015 at 12:39
• @idleberg Is it okay if your original array is tampered in the process? – thefourtheye Commented Jul 9, 2015 at 12:50
• @thefourtheye yeah, that's fine – idleberg Commented Jul 9, 2015 at 13:29

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2 Answers 2

Sorted by: Reset to default 9

You can do something like this

function shiftArray(arr, target){ 
  return arr.concat(arr.splice(0,arr.indexOf(target)));
}

var arr = ['a', 'b', 'c', 'd', 'e', 'f'];
function shiftArray(arr, target){ 
  return arr.concat(arr.splice(0,arr.indexOf(target)));
}
alert(shiftArray(arr, 'd'));

This will not modify the original array, also I remend you rename the function

function rotateArrayAround(array, pivotNeedle) {
   var pivot = array.indexOf(pivotNeedle);   
   return array.slice(pivot).concat(array.slice(0, pivot));
}